FreeLing library is licensed under Affero GPL, which means that it can not be linked to and used by proprietary software packages, and that it can not be used in proprietary web-service back-ends.
If you are interested in doing such a thing, please contact us.
The Affero-GPL license also enforces that if any changes or improvements made to the library (or the linguistic data) are distributed, it must be under the AGPL (or the original license of each data file).
Thus, if you improve the software or data, either adding new functionalities, fixing bugs, or adding analyzers for new languages, you can not distribute them under different conditions than those stated in the license.
You can get the latest development version from our GitHub repository.